Electric motor with embedded permanent magnet, compressor, and refrigeration/air-conditioning device

Abstract

In an interior permanent magnet motor, at least one magnetic pole center slit and a plurality of side slits are formed between a rotor outer peripheral surface of a rotor and a radially-outer insertion hole contour surface of a magnet insertion hole. The plurality of side slits are formed so that at least one side slit is formed on each of both sides of the magnetic pole center slit in a width direction. The area of the magnetic pole center slit is smaller than the area of each of the plurality of side slits. A width of each of the plurality of side slits is larger than an interval between the adjacent slits.

The invention claimed is: 
     
       1. An interior permanent magnet motor, comprising:
 a stator; and 
 a rotor rotatably arranged so as to be opposed to the stator, 
 wherein the rotor comprises a rotor core having a plurality of magnet insertion holes formed therein, into which corresponding permanent magnets are respectively inserted, 
 wherein at least one magnetic pole center slit and a plurality of side slits are formed between a rotor outer peripheral surface of the rotor and a radially-outer insertion hole contour surface of each of the magnet insertion holes, 
 wherein the magnetic pole center slit is arranged at a corresponding magnetic pole center, 
 wherein the plurality of side slits are formed so that at least one side slit is formed on each of both sides of the magnetic pole center slit in a width direction, 
 wherein an area of the magnetic pole center slit is smaller than an area of each of the side slits, and 
 wherein a width of each of the plurality of side slits is larger than an interval between the magnetic pole center slit and the side slit that are adjacent to each other, and is larger than an interval between the side slits that are adjacent to each other. 
 
     
     
       2. An interior permanent magnet motor according to  claim 1 , wherein a width of the magnetic pole center slit is smaller than a width of the each of the side slits. 
     
     
       3. An interior permanent magnet motor according to  claim 1 , wherein a length of the each of the plurality of side slits is larger than a length of the magnetic pole center slit. 
     
     
       4. An interior permanent magnet motor according to  claim 1 , wherein the plurality of permanent magnets and the plurality of magnet insertion holes are each formed into an arc shape that is convex toward a center side of the rotor. 
     
     
       5. A compressor, comprising, in an airtight container:
 a motor; and 
 a compression element, 
 wherein the motor comprises the interior permanent magnet motor of  claim 1 . 
 
     
     
       6. A refrigeration and air conditioning apparatus, comprising the compressor of  claim 5  as a component of a refrigeration cycle.